...The virus thrived here in part because of the usual obstacles to better health care: internal political struggles, misspent money, alleged corruption. But an unusual additional factor came into play in the hamlets along the fault line between Christians and Muslims in West Africa: Local Muslim clerics told villagers to reject the polio vaccine because it was part of an American plot.

Muslim leaders in hundreds of northern Nigerian communities such as Batakaye limited or halted door-to-door polio immunization last year. They told millions of faithful in this Muslim-dominated region that the American government had tainted the vaccine with either infertility drugs or HIV, the virus that causes AIDS -- statements later proved false by independent laboratory tests.

Some leaders admitted in interviews late last year that they never believed such a thing. But they remained silent, they said, in order to stop anything associated with the United States. The US-led wars in Iraq and Afghanistan, several said, had led them to believe that America wants to control the Islamic world, and the polio vaccination effort gave them an opportunity to resist a US-funded initiative.

They vowed to preach against polio vaccinations as long as the United States pays for them, even though it puts their own children at risk.

"People believe that America hates Muslims, and so whatever comes from the United States, no matter how good it is, people will reject it," said Sheik Muhammed Nasir Muhammed, the chief imam at the second largest mosque in Kano, the Muslim political center in northern Nigeria...

Datti Ahmed, a Muslim physician who is president of Nigeria's Supreme Council for Sharia Law, said in an interview in his courtyard in Kano that he doubts the validity of independent tests on the vaccine, which were examined by WHO, a university lab in Lagos, and by a Muslim pathologist, Abdulmumini Hassan Rafindadi, in three laboratories in northern Nigeria.

"A lot of money is being spent by interested parties to make sure they got the results they want," he said.

He also believed a US motivation existed to promote infertility drugs. "Just look at the Internet," Ahmed said. "There's strong proof that the US government, dating back to 35 years ago, with Kissinger and Nixon, believed that population is the most important factor for US hegemony in the world. Since they cannot rapidly increase the US population, the only way for them to dominate is to depopulate the Third World. This is the motive, as far as we are concerned."

Wada said opinions on the United States are divided. He said many people are angry about the wars in Iraq and Afghanistan, but nearly everyone in his small village also is aware of the US record of giving aid to poor countries.